1. Technical Field
The present disclosure generally relates to a light guiding plate and a backlight module and a display device applying the light guiding plate, in particular, to a light guiding plate suitable for side type light incidence and a backlight module and a display device applying the light guiding plate.
2. Description of Related Art
With development of flat panel display technology, a liquid crystal display (LCD) increasingly becomes a main stream of the display technology, which replaces a conventional cathode ray tube (CRT) and is widely used in daily life. Since a liquid crystal panel in the LCD cannot emit light, a backlight module is required to provide a backlight source. According to a placement position of a light emitting device, the backlight module may be divided into a direct type backlight module and a side type backlight module, in which a light guiding plate of the side type backlight module may guide a light ray from a side surface to a front side to form a surface light source.
In the side type backlight module, a light emitting device, for example, a cold cathode fluorescent lamp (CCFL), is disposed on a light incident surface on a side edge of the light guiding plate. After passing through the light incident surface and entering the light guiding plate, a light ray from the CCFL is converted to the surface light source by the light guiding plate, and output from the light guiding plate via an upper surface thereof. In addition, a lower surface of the conventional light guiding plate is usually provided with a plurality of prisms or spot patterns, for destroying total reflection of the light ray in the light guiding plate, and converting the light ray to the surface light source. The upper surface of the light guiding plate is also provided with a plurality of prisms with the same height (that is, each prism is the same), so as to enhance light output of the light guiding plate.
With the breakthrough of the manufacturing process technology, a light emitting diode (LED) increasingly replaces the CCFL to be used as the light emitting device in the backlight module. In the known design, a plurality of LEDs is arranged besides the light incident surface of the light guiding plate with intervals. However, as a point light source, the light intensity of the plurality of LEDs on the light incident surface is not uniformly distributed, in which bright regions are formed on positions corresponding to the LEDs, and a dark region is formed between two LEDs, so that the surface light source output by the light guiding plate may generate mura along an extending direction of the prisms of the upper surface. In other words, conventionally, during practical application, the side type backlight module adopting the LED as the light emitting device may have a problem of non-uniform light emergence, thereby relatively lowering display quality of the LCD.